1. Field of the Invention
The present invention relates to a sheet transportation device for an image forming apparatus and, more particularly, to a sheet transportation device having functions of performing self-diagnostics on sheet-feeding and transporting operations and self-repairing a fault.
2. Description of the Related Art
In the field of image forming apparatuses such as copying machines, a research and development has recently been conducted on self-diagnosis and self-repair functions utilizing artificial intelligence (AI) for maintenance automation.
The applicant of the present invention previously proposed a system for ensuring formation of a high quality image and, if the image quality is deteriorated, performing self-diagnosis and self-repair operations (for example, see Japanese Unexamined Patent Publication No. 4-130331 (1992)).
In terms of the maintenance of the overall image forming apparatus, however, the prior art is not satisfactory which deals only with the image quality maintenance of formed images. Therefore, it is desirable to cover a wider range of objective functions for maintenance thereof.
In recent years, a need has arisen for sequentially feeding a multiplicity of sheets for the speeding up of the operation of a copying machine. The sequential feeding of the multiplicity of sheets essentially requires improvement of the performance and stability of a sheet transportation system of the copying machine.
Unfortunately, most of presently available sheet transportation systems or mechanisms can use only limited types of sheets made of specific materials, and can be used only in a specific operational environment because of their performance unstableness toward a change in the operational environment.
The sheet transportation system per se deteriorates with time due to the aging of components thereof, thereby often causing a sheet feeding failure (e.g., plural-sheet feeding, no-sheet feeding and sheet jam). When such a failure occurs, a typical approach to the functional maintenance of the system is the cleaning of the system or the replacement of a faulty component.